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5.0 Instrumentation
The following instrumentation helps in monitoring dryer
operation and performance. Instruments which are
available as options are so noted.
Blower Purge Air dryers are rated NEMA 4 and include
the following:
• Solid State Controls
• Chamber Pressure Gauges
• Purge Flow Pressure Gauge
• Energy Management (Option A)
• Energy Management System & Dew Point Transmitter
(Option B)
5.1 Controls
The solid-state dryer controls are located in a
polycarbonate, NEMA Class 4/4X, IP66 rated electrical
enclosure mounted to a center panel located between
the two desiccant towers. Control features include:
• 15 LED's to indicate operating status and fault
conditions.
• Two line text display to provide status and diagnostic
messages.
• Upon power loss, dryer "fails safe" (inlet valve
remains in position). On power recovery, controller
resumes where power was lost.
5.2 Chamber Pressure Gauges
A gauge mounted on the gauge panel indicates which
chamber is on-stream and which is regenerating. The
gauge for the onstream tower indicates operating
pressure; the gauge for the regenerating tower indicates
0 psig.
5.3 Purge Flow Pressure Gauge
A gauge mounted on the gauge panel of the dryer
indicates purge air pressure.
5.4 Energy Management System
The optional Energy Management System (EMS)
automatically adjusts dryer operation to compensate
for changes in operating conditions. Air samples are
continuously taken from the on-stream tower and
passed over a moisture probe which senses both
temperature and relative humidity. The moisture content
of the air within the desiccant bed is then precisely
determined. The on-stream tower will not depressurize
and regenerate until a predetermined set point has been
reached. This elimination of unnecessary regeneration
reduces energy consumption and extends dryer
desiccant and component life.
5.5 Dew Point Transmitter
This option monitors and displays outlet pressure dew
points and provides an alarm signal if the dew point
exceeds user-specified set point. Recommended
calibration interval is 12 months. Contact the service
department for details.
Operation – The dew point is measured at the dryer
operating pressure and is displayed in the operator
interface. If the dew point is outside of the temperature
range, the display will indicate an over-range (high
dew point) or under-range (low dew point) condition. A
defective sensor assembly or an electronics malfunction
could also cause the transmitter to indicate under-range.
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